A low nitrogen catalytic degreasing furnace

Abstract

The utility model discloses a low-nitrogen catalytic degreasing furnace, and relates to the technical field of degreasing furnaces. The utility model includes a degreasing furnace body, an oxalic acid feeder connected to the degreasing furnace body through an acid inlet pipe, and a tail gas treatment chamber connected to the degreasing furnace body through a tail gas exhaust pipe, and also includes a vacuum pump; a vacuum pipe is connected between the vacuum pump and the degreasing furnace body, and a vacuum cut-off valve is installed on the vacuum pipe; a tail gas cut-off valve is installed on the tail gas exhaust pipe; the technical solution can perform closed vacuum treatment and the vacuum value can be set, which can greatly improve the efficiency of oxygen reduction and reduce the number and capacity of nitrogen filling; compared with the existing multiple nitrogen fillings, the time is greatly shortened and the efficiency is improved, and the cost is reduced; the structure is simple, and compared with the existing structure, only the vacuum cut-off valve, the tail gas cut-off valve and the vacuum pump are added, which can be quickly improved and applied based on the existing structure, which is convenient for market promotion and application.

Description

Technical Field

[0001] The utility model belongs to the technical field of degreasing furnaces, in particular to a low-nitrogen catalytic degreasing furnace. Background Art

[0002] Metal powder injection molding, during green body injection molding, the green body is composed of metal powder and binder. Before sintering, the binder must be removed to obtain a complete metal phase; the main component of the binder is polyoxymethylene POM, accounting for 70-95% of the total components, and the other components are materials with high melting points and good heat and oxygen resistance, such as PP, PE, etc. The catalytic degreasing of metal powder injection molding is mainly to remove polyoxymethylene, namely POM. Since the two adjacent oxygen atoms on the main chain of the polyoxymethylene molecule have a strong activation effect on the methylene hydrogen atom, the polyoxymethylene molecular chain will automatically break in an acidic atmosphere, and a chain reaction of depolymerization, namely the β chain scission mechanism, will occur, and finally the polyoxymethylene will decompose into formaldehyde gas, and the solid will become gaseous formaldehyde gas and escape from the product. It is generally called catalytic degreasing in the industry; formaldehyde gas is a flammable and explosive gas; in the existing process, in order to prevent the combustion and explosion of formaldehyde gas, catalytic degreasing is generally achieved by using a catalytic degreasing furnace.

[0003] The existing catalytic degreasing furnace process is divided into three steps: pre-flushing, catalytic degreasing, and post-flushing; specifically, nitrogen is directly filled into the degreasing furnace to discharge the internal air, thereby reducing the internal oxygen content and making the oxygen content lower than the explosion limit of formaldehyde; the explosion limit of formaldehyde is 7% to 73%, and the normal furnace oxygen content is below 5.4% and the furnace will not explode. For safety, the oxygen content of the catalytic degreasing furnace is generally controlled below 1% during operation; current technology is to introduce a certain amount of nitrogen into the catalytic degreasing furnace to achieve the purpose of oxygen control, so that the oxygen content in the furnace reaches below 1%. However, the nitrogen consumption is relatively large. For example, when the furnace chamber volume is 1000L, 1000L of nitrogen is introduced into the furnace, and the oxygen content will change from 21% to 10.5%. Then, if we want to make the oxygen content in the furnace reach 1%, we need to fill the nitrogen five times, and the specific corresponding oxygen content changes are 21%--10.5%--5.25%--2.625%--1.3125--0.656%, and a total of 5000L of nitrogen is required; the cost is relatively high. Therefore, this technical solution proposes a low-nitrogen catalytic degreasing furnace, which has less demand for nitrogen and only requires fewer times to reach the required oxygen content value. Utility Model Content

[0004] The utility model provides a low-nitrogen catalytic degreasing furnace, which comprises a vacuum pump with a vacuum shut-off valve, and an exhaust gas shut-off valve installed on an exhaust pipe; by controlling the vacuum shut-off valve, the exhaust gas shut-off valve and the vacuum pump, a closed vacuum treatment can be performed and the vacuum value can be set, which can greatly improve the efficiency of oxygen reduction and reduce the number and capacity of nitrogen filling; compared with the existing multiple nitrogen fillings that require a lot of nitrogen, the use of a vacuum pump and an electromagnetic valve has lower power consumption cost, and the required oxygen content value can be achieved in only 1-2 times, which greatly shortens the time, improves efficiency and reduces costs; in summary, the problems in the background technology are solved.

[0005] In order to solve the above technical problems, the utility model is realized by the following technical solutions:

[0006] The utility model discloses a low-nitrogen catalytic degreasing furnace, comprising a degreasing furnace body, an oxalic acid feeder connected to the degreasing furnace body through an acid inlet pipe, and an exhaust gas treatment chamber connected to the degreasing furnace body through an exhaust gas exhaust pipe, and also comprising a vacuum pump;

[0007] A vacuum pump is connected to the degreasing furnace body with a vacuum pipe, and a vacuum cut-off valve is installed on the vacuum pipe;

[0008] The exhaust gas discharge pipe is provided with an exhaust gas cut-off valve;

[0009] The vacuum pump, the vacuum pump, the vacuum cut-off valve and the vacuum cut-off valve are controlled by a PLC controller.

[0010] Furthermore, the vacuum shut-off valve and the tail gas shut-off valve are both pneumatic ball valves.

[0011] Compared with the prior art, the utility model has the following beneficial effects:

[0012] (1) The degreasing furnace includes a vacuum pump with a vacuum shut-off valve, and an exhaust gas shut-off valve installed on the exhaust pipe; by controlling the vacuum shut-off valve, the exhaust gas shut-off valve and the vacuum pump, a closed vacuum treatment can be performed and the vacuum value can be set, which can greatly improve the efficiency of oxygen reduction and reduce the number and capacity of nitrogen filling;

[0013] (2) Compared with the existing multiple nitrogen filling methods, which require a lot of nitrogen, the use of vacuum pumps and solenoid valves has lower power consumption costs and only requires 1-2 times to achieve the required oxygen content value, which greatly shortens the time, improves efficiency, and reduces costs;

[0014] (3) The structure is simple. Compared with the existing structure, only a vacuum shut-off valve, an exhaust gas shut-off valve and a vacuum pump are added. The existing structure can be quickly improved and adapted, which is convenient for market promotion and application.

[0015] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a structural schematic diagram of a low-nitrogen catalytic degreasing furnace of the utility model;

[0018] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0019] 1- degreasing furnace body, 101- tail gas treatment chamber, 102- tail gas discharge pipe, 103- tail gas cut-off valve, 2- oxalic acid feeder, 201- oxalic acid feeder, 3- vacuum pump, 301- vacuum pipe, 302- vacuum cut-off valve. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] In the description of the present invention, it should be understood that the terms "exhaust", "between", "on", "installed" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limitations on the present invention.

[0022] See also Figure 1As shown, a low-nitrogen catalytic degreasing furnace of the utility model comprises a degreasing furnace body 1, an oxalic acid feeder 2 connected to the degreasing furnace body 1 through an acid inlet pipe 201, and a tail gas treatment chamber 101 connected to the degreasing furnace body 1 through a tail gas exhaust pipe 102, and also comprises a vacuum pump 3; the corresponding degreasing furnace body 1, the degreasing furnace body 1 and the tail gas treatment chamber 101 all belong to the disclosed technology of oxalic acid furnace, and the specific structure and principle of this technical scheme are not repeated. The degreasing furnace body 1 can refer to the publication number CN110722156A, which is named as a biomass electric burner and tail gas treatment cover in a catalytic degreasing furnace common to oxalic acid and nitric acid, and the application number CN219607758U applied and disclosed by the applicant, which is named as a nitrogen-free catalytic degreasing furnace burner structure; it belongs to the disclosed technology, and can be directly connected to the tail gas exhaust pipe 102 mentioned in the technical scheme;

[0023] A vacuum tube 301 is connected between the vacuum pump 3 and the degreasing furnace body 1, and a vacuum cut-off valve 302 is installed on the vacuum tube 301; an exhaust gas cut-off valve 103 is installed on the exhaust gas exhaust pipe 102;

[0024] The vacuum pump 3 , the vacuum pump 3 , the vacuum cut-off valve 302 , and the vacuum cut-off valve 302 are controlled by a PLC controller.

[0025] The vacuum shut-off valve 302 and the tail gas shut-off valve 103 both adopt pneumatic ball valves.

[0026] Working methods, with examples:

[0027] After the product is placed in the catalytic degreasing furnace and the furnace door is closed, the tail gas exhaust pipe 102 is used for vacuum treatment, and the vacuum value can be set; if we set the vacuum value to 20Kpa, after the vacuum value reaches 20Kpa, nitrogen is added again to make the pressure in the furnace reach normal pressure. At this time, the oxygen content in the furnace directly changes from 21% to 4.2%. Then it is pumped again, and the oxygen content directly changes from 4.2% to 0.84%; the required oxygen content is reached; compared with the prior art in the background technology, it needs to be filled with nitrogen five times, and the specific corresponding oxygen content changes are 21%--10.5%--5.25%--2.625%--1.3125--0.656%, and a total of 5000L of nitrogen is required; this technical solution only needs 2000L of nitrogen, and the time is shortened by more than half, and the required power loss is greatly reduced compared with the loss of nitrogen, which greatly reduces the cost, greatly shortens the time and improves the efficiency, and reduces the cost.

[0028] The preferred embodiments of the utility model disclosed above are only used to help explain the utility model. The preferred embodiments do not describe all the details in detail, nor do they limit the utility model to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the utility model, so that technicians in the relevant technical field can well understand and use the utility model. The utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A low-nitrogen catalytic degreasing furnace, comprising a degreasing furnace body (1), an oxalic acid feeder (2) connected to the degreasing furnace body (1) through an acid inlet pipe (201), and an exhaust gas treatment chamber (101) connected to the degreasing furnace body (1) through an exhaust gas exhaust pipe (102), characterized in that: Also includes a vacuum pump (3); A vacuum pump (301) is connected between the vacuum pump (3) and the degreasing furnace body (1), and a vacuum cut-off valve (302) is installed on the vacuum pump (301); The exhaust gas discharge pipe (102) is provided with an exhaust gas shut-off valve (103); The vacuum pump (3), the vacuum pump (3), the vacuum cut-off valve (302) and the vacuum cut-off valve (302) are controlled by a PLC controller.

2. A low nitrogen catalytic degreasing furnace according to claim 1, characterized in that: The vacuum shut-off valve (302) and the tail gas shut-off valve (103) are both pneumatic ball valves.

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